Needle jogging mechanisms



Aprfl 33 1967 EWULBREDE ET AL 3,313,25

NEEDLE JOGGING MECHANISMS 4 Sheep-Sheet 1 Filed April 30. 1964 n w 0 I E m m B v W .1 D m NH R RE 6 0 n 0 Y B I 7 ATTORNEY Aprifl 1M, 1967 WULBREDE ET AL 3,313,253

NEEDLE JOGGING MECHANISMS 4 Sheets-Sheet 2 Filed April 30, 1964 INVENTORS ERNST WULBREDE BY and GERHARD SEWING m 3957 E. WULBREDE ET AL 3,313,238

NEEDLE JOGGING MECHANISMS 4 Sheets-Sheet 5 Filed April 50, 1964 INVENTORS. ERNST WULBREDE BY and GERHARD SEWING ATTORNEY 3,313,258 Patented Apr. 11, 1967 3,313,258 NEEDLE JQGGENG Ii/LECHANISMS Ernst Wulbrede and Gerhard Sewing, Karlsruhe-Hagsfeld, Germany, assignors to The Singer Comp-any, New York, N.Y., a corporation of New Jersey Filed Apr. 30, 1964, Ser. No. 363,890 6 Claims. (Cl. 112-158) This invention relates to a needle jogging mechanism for a sewing machine and more particularly to a needle jogging mechanism for a zigzag sewing machine capable of high speed operation.

In a zigzag-type sewing machine, vibratory motion in a direction transverse to the normal direction of the feeding movement of the work is imparted to the needle bar to produce the staggered punctures of the goods by the needle which are necessary in the formation of zigzag stitches. It is advantageous in the formation of such zigzag stitches to minimize the lateral movement of the needle while the needle is projecting through the goods. While the needle is in the goods, lateral movement can adversely affect the appearance of the seam by stretching or shifting the goods, it can by deflecting the needle be detrimental to proper loop seizure and thus thread concatenation, and such lateral movement can result in needle breakage.

In conventional machines, the vibratory motion is usually derived from a cam embraced by a fork-shaped pitman which transmits the resultant motion of the cam to a needle bar gate which carries the needle bar. However, in machines capable of high speed operation on the order of 3,000 stitches per minute, the fork-shaped pitman is subject to considerable wear and its operation is very noisy. In addition, the motions imparted by such cams become exceedingly harsh when the lateral movement of the needle is curtailed While the needle is projecting through the goods.

It is, therefore, an object of this invention to provide an improved needle jogging mechanism for sewing machines capable of hi h speed operation in which virtually no lateral movement is imparted to the needle while the needle is projecting through the goods to be sewn.

Another object of this invention is to provide a needle jogging mechanism for sewing machines capable of high speed operation in which there is greatly decreased wear of the parts and the operation is much quieter than has heretofore been possible.

It is an object of this invention to provide a novel arrangement of parts for generating lateral needle jogging motion with a dwell during each work penetration of the needle from a pair of eccentric means driven by the sewing machine actuating mechanism.

The above objects of this invention are accomplished by providing a shaft journaled in the bracket arm of the sewing machine and having dual eccentric means on the shaft. A pair of pitmans are pivotally connected in spaced relationship to an integrating link and each pitman is pivotally connected to one of the duel eccentric means. The integrating link is pivotally connected to a swinging arm which is in turn connected to the needle bar gate. In addition, means are provided for presetting the neutral position of the needle and the magnitude of needle jogging motion.

The resultant motion derived from the dual eccentric means is such that virtually no lateral motion is transmitted to the needle bar gate while the needle is projecting through the goods to be sewn. The pitmans cause much less wear than the conventional fork-shaped pitman and cam arrangement. As a result, the needle jogging mechanism may be operated at much greater speed than has heretofore being possible.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front elevational view, partly in vertical cross section, of a sewing machine incorporating the present invention,

FIG. 2 is an enlarged vertical cross sectional view of that portion of the sewing machine of FIG. 1 containing the two eccentrics,

FIG. 3 is a detail view of the double eccentrics of FIG. 2 after rotation in a counterclockwise direction of approximately degrees beyond the position illustrated in FIG. 2,

FIG. 4 is a cross sectional view taken substantially along the line 44 of FIG. 2,

FIG. 5 is a cross sectional view taken transversely of the sewing machine bracket arm and substantially along line 5-5 of FIG. 4, and

FIG. 6 is a graph comparing needle jogging motion with needle reciprocation.

With reference to the drawings, the invention is illustrated as incorporated in a conventional zigzag-type sewing machine having a frame which includes a work supporting bed 10 having a needle aperture 10a with a hollow standard 11 rising from one end. A hollow bracket arm 12 is connected to the top of the standard and extends laterally over the work supporting bed. The bracket arm terminates at its free end in a hollow head 13.

A main drive shaft 20 is journaled in the hollow bracket arm and extends between the standard and the head. A handwheel 21 is mounted on the main drive shaft at the standard end of the machine and rotation is imparted to the main drive shaft by means of a motor driven V-belt (not shown) tracking a belt groove 22 formed in the handwhecl.

A needle bar 36 carrying a needle 31 is endwise journaled in a needle bar gate 32 in the hollow head of the sewing machine. The needle bar gate is connected to the end of a slide rod 33 which is endwise slidably mounted in bearings 34 in the hollow bracket arm. As shown in FIG. 1, guide pins 35 set into the sewing head slidably embrace opposite sides of the needle bar gate to constrain the needle bar gate to translatory motion imparted by the slide rod 33.

Endwise reciprocation is imparted to the needle bar in a conventional manner by means of a crank 36 which is connected to the main drive shaft at its head end. A link 37 is pivotally connected between the crankpin 38 of the crank and a pivot pin 39. The pivot pin is connected to a bracket 40 which is clamped to the needle bar. The link is slidable on the pivot pin to permit lateral displacement of the needle bar simultaneously with its endwise reciprocation.

A feed dog 41 which may be associated with any conventional work feeding mechanism is located in the work supporting bed. The feed dog advances work fabrics across the work supporting bed along a line of feed in a plane indicated at 42 in FIG. 1.

'In this invention, jogging motion of the needle laterally of the line of feed is initiated by opposed identical crank means or eccentrics 50, 51 mounted on a driven transverse shaft 52 journaled in the hollow bracket arm of the sewing machine. A worm wheel 53 is also connected to the shaft on which the eccentrics are mounted, and rotation is transmitted to the worn wheel in timed relationship with the endwise reciprocation of the needle by means of a worm 54 mounted on the main drive shaft. In a preferred embodiment of the invention, the driven transverse shaft on which the eccentrics are mounted rotates once for every two rotations of the main shaft.

The eccentrics are embraced by a pair of pitman straps 55, 56. The pitman straps are pivotally connected in spaced relationship to opposite faces of an integrating link 57 by pivot pins 58, 59. Depending fingers 60 on the integrating link serve to maintain the pitman straps in parallel planes on opposed surfaces of the integrating link.

The resultant motion of the integrating link as derived from the eccentrics 50, 51 is transmitted to the needle bar gate 32 by means of a connecting means or swinging arm 61 to which the integrating link is pivotally connected by means of a pivot pin 62 equidistant from the pivot pins 58, 59. The swinging arm is pivotally connected by means of a pivot pin 63 to a bracket 64 clamped on the slide rod 33 to which the needle bar gate is connected.

The other end of the swinging arm is formed with bifurcate arms 65 which are journaled on a spacer 66. A transverse bore 67 formed diametrically through the spacer constitutes a sliding connection to a pin 68 which is held in the yoke of an adjustable frame 69 mounted to be turned on a horizontal axis. It is the preset angular orientation of the pin 68 about the axis of the frame 69 which determines what component of the total motion of the swinging arm 61 will be converted into the lateral jogging motion imparted to the needle.

In a preferred embodiment of the invention using the eccentricity or the distance between the axis of the shaft 52 for eccentrics 50, 51 and the geometric center of either eccentric 50, 51 as a base and ascribing to it a value of one, it has been found that the following proportional relationships of other portions of the mechanism provide the desired periods of dwell while the needle is projecting through goods placed on the work support and while the needle is jogged laterally at an amplitude of of an inch. The geometric Centers 70, 71 of the eccentrics are approximately 80 degrees apart on the arc of a circle which is coaxial with the shaft for the eccentrics. The distance from the geometric center of either eccentric 50, 51 to the axis of the pivot pin 58 or 59 respectively by which the eccentrics are operatively connected to the integrating link 57 is approximately 2.25 times the eccentricity of the eccentrics. The distance between the axes of the pivot pins 58, 59 along the integrating link is approximately 2.5 times the eccentricity of the eccentrics, and the height of the isosceles triangle formed by the axes of the pivot pins 58, 59 and 62 is 2.8 times the eccentricity.

In addition to the foregoing relationships, the axes of the shaft 52 for the eccentrics and of the pivot pin 63 by which the swinging arm 61 is operatively connected to the needle bar gate 32 defines a plane which is substantially mutually perpendicular to a median plane defined by the axes of the shaft for the eccentrics and the pivot pin 62 by which the integrating link 57 is connected to the swinging arm. The distance between the axes of the pivot pins 62, 63 along the swinging arm is approximate ly 12 times the eccentricity of the eccentrics.

The neutral position of the needle is set by means of telescoped eccentric bushings 80, 81 which shift the pin 68 laterally. A stud 82 protrudes from the outer surface of the frame 69 and is journaled in the eccentric bushing 80. The eccentric bushing 80 is in turn journaled in the eccentric bushing 81 which is journaled in the hollow standard. A handle 83 is connected to the end of the outermost eccentric bushing 81 and by turning the handle the position of the pin 68 may be shifted bodily within the machine frame to preset the neutral position of the needle. Screw pins 84, 85 protruding from the end of the outermost eccentric bushing 81 coacting with bolt stops 86 held in a bracket 87 define the maximum possible neutral position to the right and left of center. A spring 88 cantilevered on the inside of the hollow standard provides friction to maintain the various settings, and a curvilinear portion 89 formed in the spring embraces the uppermost screw pin 84 to indicate center neutral posi- A tion for the needle. Pivotally connected to the end of the inner eccentric bushing is a slide block 90. The slide block slides in a slideway 91 formed in the bracket 87 which is connected to the inside of the hollow standard.

The angular orientation of the pin 68 and hence the maximum displacement of the needle is controlled by a handle 100. The handle 100 is secured on the outer end of a shaft 100 (FIG. 2) that is connected at one end through a link 103 to a slideway member 101 which embraces a slide block 102 pivotally connected to an extension of the frame 69. The slideway member is additionally supported by being pivotally connected at its other end to a link 164.

In operation, with particular reference to FIG. 6, the shaft 52 for the eccentrics rotates one-half as fast as the main drive shaft 20 through the worm 54 and the worm wheel 53 as mentioned previously. The shaft 52 for the eccentrics in the position illustrated in FIG. 2 is oriented in a position corresponding to that indicated as 0 degree in FIG. 6, in which position of parts the needle is both in its lowermost position and its leftmost position when set for zigzag operation and as viewed from the front of the machine. In FIG. 6, the crosshatched portions indicate the periods during which the needle is penetrating the goods.

The main drive shaft 20 rotating in the direction shown by the arrow 111 in FIG. 5 rotates the shaft 52 for the eccentrics 50, 51 in the direction shown by the arrow 112 in FIG. 2. For approximately 40 degrees of rotation beyond the position of parts illustrated in FIG. 2, the eccentrics 50, 51 impart virtually no lateral motion to the slide rod 33 and hence to the needle which is still projecting through the goods on the work supporting bed. The pitman straps 55, 56 simply follow the eccentrics 50, 51 to pivot the integrating link 57 about the pivot pin 62 which comprises the pivotal connection of the integrating link to the swinging arm 61.

Beyond 40 degrees, however, the motion imparted by the eccentrics 50, 51 causes the pivot pin 62 to rise as shown in FIG. 3 and the swinging arm 61 to slide up on the pin 68 to shift the slide rod 33 to the right when the pin 68 is set for zigzag operation. The needle is in approximately its midpoint position in FIG. 3 and the shaft for the eccentrics 52 has rotated approximately degrees beyond the position illustrated in FIG. 2. After the shaft for the eccentrics has rotated approximately 140 degrees beyond the position illustrated in FIG. 2, the needle is shifted to its rightmost position and begins to penetrate the goods a second time. Again from approximately 140 degrees to approximately 220 degrees virtually no lateral motion is imparted to the needle while it is projecting through goods on the work supporting bed. The pitman straps 55, 56 again cause the integrating link 57 to simply pivot around the pivot pin 62. After approximately 220 degrees of rotation, the needle is again jogged to the left until the dwell period for the leftmost needle penetration begins after approximately 320 degrees of rotation of the shaft 52 for the eccentrics.

As previously mentioned the neutral position of the needle is determined by the orientation of the eccentric bushings 80, 81. When the handle 83 is moved upward, the outer eccentric bushing 31 is rotated clockwise. Simultaneously, the inner eccentric bushing 80 which is constrained by the slideway 91 slidingly pivots generally in a counterclockwise direction to shift the stud 82 and the pin 68 downward and to the left as viewed in FIG. 1. The leftward movement of the pin 68 shifts the neutral position of the needle to the left. Conversely, movement of the handle downward moves the pin upward and to the right to shift the neutral position of the needle to the right.

The handle controls the angular orientation of the slideway 101 and the pin 68 which determins the magnitude of the lateral displacement of the needle. When the handle 100 is moved to the left from the position shown in FIG. 1, the slideway 101 is shifted counterclockwise on the links 103, 104 to shift the frame 69 and the pin 68 clockwise. With the angle of the pin 68 canted away from the vertical, angular movement of the swinging arm 61 about the pivot pin 63 generates a lateral component of motion as the spacer 66 slides up and down on the pin 68. The periods of dwell imposed by the eccentrics 59, 51 and the integrating link 57 are not affected by the angular orientation of the pin 68.

When the pin 68 is tangent to a circle coaxial with the pivot pin 63 virtually no lateral motion is transmitted to the needle and the machine sews as a straight stitch sewing machine. It is of course Within the scope of the invention to have the pin 68 and slideway 101 and associated mechanisms in any desired position relatively to the double eccentrics 5t), 51 with appropriate dimensional adjustments.

Although the invention has been described in its preferred form with a certain degree of particularly, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.

What is claimed is:

1. A needle jogging mechanism for a sewing machine having a frame, a work support on the frame having an aperture, a needle bar gate, means connected to the needle bar gate and mounted on the frame for permitting lateral oscillation of the needle bar gate, a needle bar, a needle connected to the needle bar, means for mounting the needle bar on the needle bar gate for endwise reciprocation of the needle into and out of the aperture in the Work support, and means for imparting endwise reciprocation to the needle bar, said needle jogging mechanism comprising a shaft, means for journaling the shaft on the frame, means for rotating the shaft in timed relation with reciprocation of the needle, two crank means on the shaft oriented around the shaft in spaced angular relationship to each other, two pitmans, one pitman pivotally connected to one of the crank means and the other pitman pivotally connected to the other of the crank means, and integrating link, first and second pivot means in spaced relation to each other on the intergrating link for connecting the pitmans to the integrating link, connecting means for trasmitting lateral oscillation to the needle bar gate, and third pivot means for connecting the integrating link to the connecting means; the angular velocity and timing of the shaft relative to reciprocation of the needle, the magnitude of the spaced angular relationship between the crank means, and the mutual distances between the axes of the shaft, the crank means and the three pivot means being such that during the time when the needle is projecting into the aperture in the work support the crank means pivot the integrating link around the third pivot means which connect the integrating link to the connecting means substantially without shifting said third pivot means in a way that no lateral oscillation can be imparted to the needle bar gate and when the needle is out of the aperture in the work support the crank means can shift said third pivot means laterally to impart lateral oscillation to the needle bar gate.

2. The needle jogging mechanism of claim 1 in which the crank means are eccentrics and the pitmans have pitman straps which embrace the eccentrics.

3. The needle jogging mechanism of claim 1 in which the magnitude of the spaced angular relationship between the crank means is approximately degrees.

4. The needle jogging mechanism of claim 1 which includes slideway means mounted on the frame, means for slidably connecting the connecting means to the slideway means, and means for changing the angular orientation of the slideway means for changing the amplitude of lateral oscillation of the needle bar gate.

5. The needle jogging mechanism of claim 1 in which the distances between the axes of the third and first pivot means and the third and second pivot means are equal.

6. The needle jogging mechanism of claim 5 in which the distances between the axes of the shaft and each one of the crank means are equal and relative to the eccen' tricity of the crank means defined as the distance between the axes of the shaft and either one of the crank means; the distances between the axes of the first pivot means and its connected crank means and the second pivot means and its connected crank means are approximately 2.25 times the eccentricity, the distance between the first and second pivot means is approximately 2.5 times the eccentricity, and the height of the isosceles triangle formed by the three pivot means is approximately 2.8 times the eccentricity.

References Cited by the Examiner UNITED STATES PATENTS 7/1941 Avis 112159 2/1943 Hale 112158 

1. A NEEDLE JOGGING MECHANISM FOR A SEWING MACHINE HAVING A FRAME, A WORK SUPPORT ON THE FRAME HAVING AN APERTURE, A NEEDLE BAR GATE, MEANS CONNECTED TO THE NEEDLE BAR GATE AND MOUNTED ON THE FRAME FOR PERMITTING LATERAL OSCILLATION OF THE NEEDLE BAR GATE, A NEEDLE BAR, A NEEDLE CONNECTED TO THE NEEDLE BAR, MEANS FOR MOUNTING THE NEEDLE BAR ON THE NEEDLE BAR GATE FOR ENDWISE RECIPROCATION OF THE NEEDLE INTO AND OUT OF THE APERTURE IN THE WORK SUPPORT, AND MEANS FOR IMPARTING ENDWISE RECIPROCATION TO THE NEEDLE BAR, SAID NEEDLE JOGGING MECHANISM COMPRISING A SHAFT, MEANS FOR JOURNALING THE SHAFT ON THE FRAME, MEANS FOR ROTATING THE SHAFT IN TIMED RELATION WITH RECIPROCATION OF THE NEEDLE, TWO CRANK MEANS ON THE SHAFT ORIENTED AROUND THE SHAFT IN SPACED ANGULAR RELATIONSHIP TO EACH OTHER, TWO PITMANS, ONE PITMAN PIVOTALLY CONNECTED TO ONE OF THE CRANK MEANS AND THE OTHER PITMAN PIVOTALLY CONNECTED TO THE OTHER OF THE CRANK MEANS, AND INTEGRATING LINK, FIRST AND SECOND PIVOT MEANS IN SPACED RELATION TO EACH OTHER ON THE INTERGRATING LINK FOR CONNECTING THE PITMANS TO THE INTEGRATING LINK, CONNECTING MEANS FOR TRANSMITTING LATERAL OSCILLATION TO THE NEEDLE BAR GATE, AND THIRD PIVOT MEANS FOR CONNECTING THE INTEGRATING LINK TO THE CONNECTING MEANS; THE ANGULAR VELOCITY AND TIMING OF THE SHAFT RELATIVE TO RECIPROCATION OF THE NEEDLE, THE MAGNITUDE OF THE SPACED ANGULAR RELATIONSHIP BETWEEN THE CRANK MEANS, AND THE MUTUAL DISTANCES BETWEEN THE AXES OF THE SHAFT, THE CRANK MEANS AND THE THREE PIVOT MEANS BEING SUCH THAT DURING THE TIME WHEN THE NEEDLE IS PROJECTING INTO THE APERTURE IN THE WORK SUPPORT THE CRANK MEANS PIVOT THE INTEGRATING LINK AROUND THE THIRD PIVOT MEANS WHICH CONNECT THE INTEGRATING LINK TO THE CONNECTING MEANS SUBSTANTIALLY WITHOUT SHIFTING SAID THIRD PIVOT MEANS IN A WAY THAT NO LATERAL OSCILLATION CAN BE IMPARTED TO THE NEEDLE BAR GATE AND WHEN THE NEEDLE IS OUT OF THE APERTURE IN THE WORK SUPPORT THE CRANK MEANS CAN SHIFT SAID THIRD PIVOT MEANS LATERALLY TO IMPART LATERAL OSCILLATION TO THE NEEDLE BAR GATE. 